SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46aea8d441e00b7f4d0b43b946fd00b925fa3a68940f33299effff15a9e4d3e1' 
  AND token = 'kPhnMDDrSnQHB1I2rqgnVFWa2c3IOGDTYBlB7IP++sA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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