SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab88429121cd6dfb2fc2abfcecec24dac631e884eec728fa07eeb66238e74529' 
  AND token = 'n5/isCqDN7fp1qBZl0jH/2X3qBh/38JC51fxvmP2V3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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