SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2c3aeae7b18927c5fcec2137de3f0fb5073dff27379d14f326609a19959b98a' 
  AND token = '0iB0k4Y7mKnWaWh4jNWlPJEeZWThjaz4G4pbjIqmI3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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