SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12e43511913f480009e9a782b0b9aad22c510fcff9b269b995225e14b1606bc8' 
  AND token = 'nUY4gb+/AH7LbpYnlZEvbP0pqrMRvyGLjKtQAr7f2G4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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