SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1efa353de2ec9d089951861462d0d83e192d3205c6cd9269d822658f0b1918e' 
  AND token = '9q/T0qmIiyFs887u65FUDosz3RAAJORmUjTYgPvncBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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