SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4be85b5a0ceee00e23031edf3af691ddf03e23d39373e495ddb29f3d04a44bcf' 
  AND token = 'lc/p4LaxJUVFTi8vPXSWRmQtipLvw4ioGuKOhaYsYhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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