SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '36476e66dd84a2dc06ddd2ed909666a545ae83a9a11b54ff89b6c1f4d6c3c98b' 
  AND token = 'ZFvVR1yH4RmUs5vumTnwkfkKdmV635BMTYETfQ1ULQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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