SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e81b389fa4cf7dca74d1e63f2dc233231d00196e58ecead0ff443daefa4d37f' 
  AND token = 'GiW3RgdU1WYuKEpR6LErh6RkA9+bpBXTlnguMDbmEok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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