SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a2b3c36f34fe73ac6af0a2568b5c711621f6c4b62f09637fece9b3e9bf01fca' 
  AND token = 'L1dBOapFPTtx3KpnLlrtHVcuGDB4pFBLC2vnExXDHgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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