SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12cd6cb96cabeb5bed478c48cd3e46156c0072ff2ccaff915eb2abf1eb2dfb64' 
  AND token = '0ouHhqPpbE32CBVqIgO3ha1QR8wtJzzPK62h77GwpPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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