SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c69f49a41660bf3124993a8d41c57a0141bc8b85ecde103691a8e5787df047b2' 
  AND token = 'SNMRxCkdguxEhxZsrT7FYgOU4kJCCbpVhbEDhltYW3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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