SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3962b08c83e879622799d20569a1b974bcd87d36b99b2a0b956ea6d0133e5dd' 
  AND token = 'Rl0we0/GqgziXklbhoOuKNJT5mlXn5I/4UuDpkEXNNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}