SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b6815f6a0581fb6eb4d363cee70469f7693debb4fc22227468730424787f9491' 
  AND token = 'OmUYm2lCdI4TXALzqewh0BwAeGaLo1Y0E3/RF+tBEIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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