SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '704a970150faa76866656e576d94885bcd17e02a68dfe98e170210ee1cd9a362' 
  AND token = 'nm2ZA+Y+3kQD+2lKEYG6PJlwWvNBihtrHgEOz0oV0gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}