SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '82f7ec499267b0295652830ae1489ab533d2750eb071077e8c96667d576b944c' 
  AND token = 'CzHghhwoq7EkCnY0gq0zEku9Qc6tFix3ZffsWf6rRGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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