SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dedd5460f99008afa833abbbedde9c1eb9dffda17dfb1136116aa0c3adce9ac' 
  AND token = 'ML0I5XE4TaITmIRlnoePsvPoyJZ6rnP3eBIL1bX/RYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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