SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d91342041582f9d1c92cc9e9eeb389d93646761e131e50a9feec4c6a5242d5a' 
  AND token = 'hCZPwDN6srrHMSDQCzY+XNTSs8Yu1ym60j0COekHe7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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