SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1afedb55738db31e428db73b603166676434d20ba7c88870d7d01f507ea6b392' 
  AND token = 'qe0rEAUrMu2zZpyZrR4DiPqsO1NvAanwnZic0wQF3eU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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