SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb5e420d8eba5cb6e6d1c2cecc81ad5a414e81c4fe9ae62dbfffd517403a69a3' 
  AND token = '7cOVhrV8a96XV1nnz8LJ3fantYi4WjFxDZ1pC9P4KxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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