SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3eb14e906d8967748325d3ef813f5f632acd76301b7643117025e32d9aba2741' 
  AND token = 'v2orV56zsLmWldiWuN/SVCZgP+prI0RHJxA+Rwh5pyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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