SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0988a2aa3d611f2b2e4d6b0f0482c8591ece0862c1050979a378e13be07ac68c' 
  AND token = 'UBiVFOYag3gn+qx4K2fBiHfPawAH6mgujcDzHUZoqEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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