SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62f94b8a4a06c58e31bf5642084eaeb7f8ddeb75667a9fdece588e335aaf404a' 
  AND token = 'QI+WK4VReHTfE2NICk1vxsMHGOaJbCpdIkgJgCnLaME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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