SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd245c7fdb57393972cbb0673a979e375bf1ba14e72d3a78dfcee8fd4f87dfd9' 
  AND token = 'VotRoPQsuoH2HN5gAlWrMGvqHTTnLVnEN/48gVg4cn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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