SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54e6a143462a4e1bc0f168c7dad852a6044ae6c429a88799257c4d1a2fda5e92' 
  AND token = 'J5O6NyVQpYNhnXUKRDtCUSbqcgnS6h2rNEB/z1ABoTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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