SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7143ef323644e75e0937d31b9af09a65ed1ed0a886f9bd7fe2476d6f73c146e3' 
  AND token = 'sQ9qGzVFITvHzF025KlG7LsoqTaDm7YU9tf/uLmU418=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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