SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20f840b686a3c6a1bd88c53859f204b1d8643170d293ea2316891ef2c78e44f1' 
  AND token = '9gN6NGUUdArtXrROF/BJudxP3+BhZLylnKnDQNKs4fw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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