SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '611ef3a096105ed434116b729ec9bf643d51eefc5df183f5033834891c4a39ce' 
  AND token = '8/OEzSxzSyWX3IeQlxeP413iKuYwC/GK+300XBoo+t4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}