SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89b746126dbdaa1153e6a36196c7754c55024e632580afd6840004e4cbe6afa4' 
  AND token = 'MehPvfR4B1iG3eiK15cjG4bOhQ2YWRir/MEUineefrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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