SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da7c8393b51a2b306bff03d1eebc6758aee684b12cdd286eb1c8a48d3a79c779' 
  AND token = 'Odwt1QKQRGMf+j0PJnq3aH9ZKYpYXR38mVJbVZTaoBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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