SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fe5d43cc2030cc20afb050e32a9a1df756685f83950d0b7575152d3ed193ec06' 
  AND token = 'ZZ3ja03/Uy3aDO5jUhaA8T4z+VTGEHE4ZiLBn3nDsXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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