SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1a27678cf8217af25ad6faffb53e9a42ccd09524ed8648fe63ad20f8aed1e6a6' 
  AND token = 'HY0LrZVRy8lapc+g/mEZWqhXr7NGmQmblFUw1EnsqZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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