SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50afad8dbe88874f21a2ead1d3092c640c814328606ed58601b4c2f4a794f318' 
  AND token = 'GgrzTfIc2WhEFFGVKLuAp1UdIN8PEMK1uCK4p0iMdUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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