SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a0dd6f8522c1a67da5740f37e03fd95c8ef21a2cbe8a68507515fb83a64ef1f' 
  AND token = 'I82Kto280pk42E1BLtVq49hZp7YZoqksLAZuLVTb/tA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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