SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e52c90a1eb8c66b1b034721a5c2cf501e9e873bdce6adc1ebedec335ddf88dbd' 
  AND token = 'F8Umirs4JooD54CtQPedF2VFwu4FuCcMJRXBUB8GEoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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