SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e40cb3c39ab459db45307ea6e81bffe6d33ad1ae9d3e0b805170a00833a9550d' 
  AND token = 'T35hXf5iXZUcM9ENAyRNpzJceoRI2AlcWV59R6E2SUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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