SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f750e61b37e32a6f844416f4c32fbcb1b147d57ab75683d0cd5268266c1e9be' 
  AND token = 'j9T36DPfORX+vIzjmoZ9lwIoOo411Ma1Kit/8yVBBvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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