SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b80093c4431c7a2e21b36156713fd802ac9a071040e25ecca363a0c6e6be1ecc' 
  AND token = 'OK7jms6lFA/yA6SRdshgv49UleGCJUfLLyzl59URFsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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