SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1e441472c0b22615e9282261812e3c6ca3fa5a1c7915e191cabe9d5a5eb749d' 
  AND token = '2UM9oxhltnhA5dX3ze8U8ucK7cyAJ+g/6m7z7PDnQMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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