SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e74e4031017cd369e3aaee1006d8868562c33717bddcb1d6ff914b8e12d2393' 
  AND token = 'XddqkWA2hf55zCVlduaKQYEz/hhQVLhPXFT1h2hYIOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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