SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b6652fb1519b437569f82a41355606cf6196ce8806f67c9317e5c94e0fd30e6' 
  AND token = 'VrJLWyWQzHn12dv/rV7P5HWTBvPMamLvwnnJzQF0xSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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