SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6a6a6338fc2bc77630615d8c9ec29052501758fe825a068260dd118d62d05a8' 
  AND token = 'KxE8Ozh/spp6f1K8JnUjWTNPRMglZXFsjU4CW+MGAHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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