SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48a68dcb37b00473cdd1e4681c3936a830a3eb82a04d575a818acaef89af681f' 
  AND token = 'fgLAX0SjEQxzMiL7XRB2z45lSx7VAxFH7hke/L1CYkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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