SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1a8fa5f2acdfbbcf494b97503a98170c1998bc6965e8ec194ef594395af734b' 
  AND token = 'gN8/bg0AqemkHTVvWepT5OtVxyErOgpiZKQE0uEoD/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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