SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b367899507a52a9158cc9f3756bcdb0ed86a464704958d5639a176c6e3ff4c4b' 
  AND token = 'jgmje97QI2WeV7sXzYIVv5lzqJUnrNZLDSVM0krR+3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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