SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36cbaee2dc450abc3c4760e20f9aa439b904666520be4e9a4628731b4d79ca56' 
  AND token = 'qbztqMXbMwURirpxE/KMy0kcv+l9TsOSHOpQZHAP9ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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