SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd23ce52b488853fa3e9dd062a0d036e15567c3489484b98764eb51031ca725f7' 
  AND token = 'm9L0Ny6OTDjOsuHODHY9qn5f+fAnZmjLH6heNM5unMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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