SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd4cfdc81234dd575ff7b2a6f591aa5d1a82c6871ca106e7645dd8439daa96f0' 
  AND token = 'wsaE7L0vQKjLIJeJ6YxvMsg/gnCJUWOrenGlQnJfxVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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