SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1035c2b87762fa146cd5a065068024495e57da14788165110b6854dd6b6ed3d' 
  AND token = '+jpeLZ3QAnGkwcq6WbMuijFPqV1O5tFxTAFRxKBpXzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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