SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6dfe6550c1ecffb182812de6872e1af93650de2a625731affb4126d06d62bea7' 
  AND token = 'K+Mr1fXM815MJaygMRdMWxasn4T2HomELMrKelq44b8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}