SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6d284e79ed15d3fab8f436b314b68679763df25c5e3af531883d78faedf5e3dc' 
  AND token = '3IkQwJyDbZ7+euLps+VSx2MPYX0sIAcql6pjHdPBIag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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