SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69bda5e18fa3e6226420bb9cd84ce891511f6957eb3ff2036639cfdffda6c312' 
  AND token = 'GjiFhDoEvC0qY1ShtDtA8CdojdJZRZGBe9oNgarXJn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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