SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2e0b35c73317636fc3b5b033ef160570a7c4cb394aa23552021f4b434e6b6c0' 
  AND token = 'c7zt47aN+xQQ5VsiF6/mn/FZKLvXBFhqoTZdM1D9/2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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