SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e676304e222848ba7c563f9c827bc38633924ac45fc19459a096383dc1858af' 
  AND token = 'iAOtvm30W29oylYQI+v/VgQGc2WKyyvTo3KO0hw+T6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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