SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3fbc083807d598e8ce2820aaebc591a3f9acd75f5c829009996bc7b0b408d9e' 
  AND token = 'nxeU2vLUoX1ByB5S6gjXA0KWYQsjEFLiD9IttjpY95M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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