SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '152e8867877643f6301dcc6706e2992bdd76db1104f5fbecf39612f1dce5a3f2' 
  AND token = 'YFDJQWwbVSgiHvqUeEkaQh/UW385fDy4bAT3VPeZwGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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