SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '278cb55b2dc59ef379257538293da99abb4fbef8aee4e2cfb46e64bcac1e9537' 
  AND token = 'tLTklGAvlqFiymcDx2Qq7KF5mKltgVG47UDlIWj4Vy0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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