SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68c147881c8a3ce54cdbe4dd6b45bfb54aad01c74b2d528099190fe17639205d' 
  AND token = 'J1uPfbsgcXi5B1nf92FE0dwhO/FYNTHWjzGYdBRIeEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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