SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '357935342c0eb53c88891196f3c2ecd3bca0ac8dac0ade4b5830de9abf6bf729' 
  AND token = 'EtyfELJ4VHiy3vsWJuHbiow3BXTrB6bxDvsPzWMpiwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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