SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '678e110b1eb52b6e23289795d62a2398709c225c58c810a96edfe7f2c551d776' 
  AND token = 'oPaHITkK94eMEulRoNykrWL3tdS3+8okGCfa0QwtsKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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