SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aa73204ff981b38bfd8399acbb3f6d373df2243966e48cf005543c9ab28a0c7' 
  AND token = '54iHownDzTOR+gtmGsiyvRLufmfquL5uLQ5U3o7EtvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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