SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68f412244e7363ad169dca674f7347588c3d3bb03bdb57878132a62d7f321bbb' 
  AND token = 'mEumsbIbHv8X22aw5gfgc0+Nc6gxp5hRO0O8yAd7pq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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