SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c371239eaf4d1f7a1cd836c818d179c58c2c81e621535a2f01305320288fafe3' 
  AND token = 'ZcyhGXp16awKSIGhekqbKHtbpvmeI3ex3XLThM/nqZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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