SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52ddcb7892c544300731cab5bec2a88013212bfbe6d79a23e4eac8f317f52d40' 
  AND token = 'Q/MN5q8wx3LE83PpKGylrYfq9yYaXiUo8QwtaBzhJBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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