SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7018aeb2e15746a188872e4b39a98d97e27d5418a2ea4bd7aaeceb114a14c8c' 
  AND token = 'fDo9tW4LkdbXJUF3SwASCS6mOK9vYUjUY2JZYf7pWdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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