SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0dceec779986a8a86143afa4afc81ecdf4c5a04c5aa4b98b63a2e45bda83b5c' 
  AND token = 'OQSA64XTYrmCrOPMwtSyMtKc2+QwCCqYTBERzhniexE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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