SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c67a0c79761301ece9065b1696880b59496f2b9463b6d6b561259371d993549' 
  AND token = 'ogOSlf3Wt0NAYusWetZkDIR5yjLo54aqxsBTXy39lEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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