SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d970b4c05bfc0eec26cc21f1f22991a523dcaf5bb71460d805522075d79d3be' 
  AND token = 'VOfnu4sjcvhIgKYvze9W/nryN/ZlLaqUaLnMK51y+Dw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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