SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c7fdbe485ce594823d4460e48181d9e5197692f52a145969033c014a5a182c1' 
  AND token = '2ZL2bvr1nUyLcjKYF5d8SDlICxgkMPbBYiewvMU2BG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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