SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6161354382d68740261e544ec1ed3571ee2fe272b568585cadc7c78b3e60c287' 
  AND token = 'bPs/FjRR6Nr/hjQEDnZdEe8fizIS5uXr7z3aKPoQmX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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