SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddf7cd452554d15fa01c374a28bf2a1c0a04b263b91a744ab4896d322e91ff12' 
  AND token = 'IWpLqyfx1fq2iI+OYth9zRZL0R/8VD8cBbTB862KZh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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